For many centuries, a variety of treatments and potions designed to treat skin problems of all types have been widely utilized. Numerous attempts to improve the appearance of skin by retardation, halting, or even reversal of the aging process have involved application of many different procedures and agents. For example, petroleum-based oils, creams, and solutions have, over the years, been topically applied in order to improve or prevent wrinkles, dryness, and to generally improve the appearance of skin. In addition, many compounds and solutions for fading various pigmented lesions resulting from exposure to sun and which typically worsen with age have been applied. The failure of such treatments to adequately address the desires of a populace concerned with the preservation of youthful-looking skin has led to the development of many cosmetic surgical procedures and high-technology cosmetic compounds which attempt to alleviate the effects of aging.
For over a century, physicians have been attempting to obliterate some of those undesired wrinkles and skin damage caused by exposure to sunlight, as well as scars and other skin problems, such as pigmentary dyschromias, by applying escharotic, or caustic peeling, agents to the skin. Since the early 1960's, the formulas and method for application of escharotic agents have been subject to sophisticated histologic studies and refined as such procedures have become more commonly utilized.
Escharotic agents for peeling skin which have been utilized over the years include phenol, resorcinol, salicylic acid, pyruvic acid, methyl salicylate, glycolic and other fruit-based or alpha-hydroxy acid, azelaic acid and trichloroacetic acid. Such escharotic agents have been used on various skin surfaces of the body in order to produce peeling designed to treat a diverse range of skin conditions, including scarring resulting from acne, bums, brasions or other skin injuries, pigmentary dyschromias, actinic keratoses, enlarged pores or philosebaceous follicles, rhytides, and more pronounced wrinkles, and other actinic damage to skin.
A peel applied to correct such skin problems is generally classified, according to the depth of the wound produced, as either superficial, medium-depth or deep-depth. Superficial wounding is defined as the wounding of portions of the epidermis alone or through the papillary dermis. Medium-depth wounding extends to the upper portion of the reticular dermis, and deep-depth wounding extends to the mid-reticular dermis. The depth of the peel administered is based on the indications of the particular skin condition being treated. Generally, although a superficial peel may be adequate for treatment of mild scarring and pigmentation dyschromias of the skin, deep peels are most effective for treatment of the majority of skin problems, such as deeper scarring, serious sun damage, skin laxity, and dermal pigmentation.
Unfortunately, however, there are many contraindications for performing deep peels with conventional phenol agents and dermabrasion. Inevitable hypopigmentation resulting from impairment of melanin synthesis in the deep peel process produces a permanent difference in the shade of the peels as compared to the untreated skin, and renders the peeled skin prone to uneven pigmentation when exposed to sunlight. Moreover, the texture and appearance of the skin of the patient being treated is also permanently altered due to the permanent destruction of hair follicles and collagen. In addition, increased risk of scarring and atrophy, or clinical loss of abnormal skin markings, is more likely to occur as an adverse side effect of a deep peel.
Furthermore, even deep peels are ineffective for correcting certain types of scars, such as deep "ice pick" scars with sharp edges and deep pits. Nor have other methods of medical treatment achieved satisfactory smoothing of such "ice pick" scars. Those treatments include dermabrasion, punch grafting and elevation (making an incision in and sewing the wound), soft tissue-filling agents such as collagen (Zyplast, Zyderm, Collagen Corp., Palo Alto, Calif.), silicone, Fibrel (commercially available from Mentor Corp., Santa Barbara, Calif.), or autologous fats, and excision. Not only are such medical procedures ineffective for flattening "ice pick" scars, there are additional problems. For instance, in applying dermabrasion, the depth of the peel is imprecise, difficult to control, and highly dependent upon the individual physician's skill in using the dermabrasion instrument. Moreover, the healing or recovery period for dermabrasion, as well as chemical peel, patients is quite long and often involves convalescence of one to three weeks or longer, as the unsightly appearance of the treated area prevents many patients from venturing outside of their homes in order to perform their normal daily routine. The smoothing effect of soft tissue-filling agents, as well as punch grafting and elevation, are notoriously short-lived, rarely lasting beyond one year and often disintegrating within the first six months after application.
Continuing dissatisfaction with existing treatment for skin problems led to further development, and, in the early 1980's, when wrinkle pharmacology based on the acceleration of exfoliation and desquamation of the skin emerged through the discovery that the acne drug Retin-A or tretinoin, removed fine lines. Since that time, a variety of exfoliation agents for reducing wrinkles have been utilized. Now, glycolic acid, salicylic acid, lactic acid, alpha hydroxy or fruit acids, as well as other exfoliants, are being incorporated in cosmetic creams in order to aid and accelerate natural cell-shedding of the skin.
Other substances have also been utilized in cosmetic compositions developed during the recent anti-wrinkle revolution. For example, ceramide creams, which are reported to repair and enhance the binding process of surface skin cells and to actively hydrate and reinforce the skin's barrier against environmental assault, have recently been formulated. Vitamin H and vitamin C are also being used in cosmetic compositions, and the manufacturers of such compositions claim that these vitamins are capable of fortifying skin cells and resisting the ill effects of the environment.
In recent years, liposomes have been used, ostensibly for transporting compounds within the inner cells of the skin, in a variety of creams, lotions, and gels manufactured by many companies.
Unfortunately, however, neither cosmetic surgical procedures nor cosmetic creams of the past have been capable of successfully preventing or correcting a lesion or crevice, particularly when it is deeply recessed in the epidermal and dermal tissue. To the contrary, there has not thus far been a substance or mechanism for carrying and delivering the foregoing and other compositions deep into the skin, particularly to penetrate hair follicles, sebaceous glands, "ice pick" scars, and other deep crevices traversing the epidermis and dermis tissue and of the skin. There is a further need for a system whereby cosmetic or medicinal agents, especially those that are intrusive, such as escharotic agents, used to treat such and other skin imperfections, which enables localization of the agent so as to prevent undesired contact of the agent with surrounding normal skin surfaces. Therefore, it is apparent that the need for a delivery system addressing such and other problems persists.